Light Bulb Calculator
Is your room too dim or too bright? Enter the room dimensions and type, and this calculator tells you exactly how many lumens you need, the LED wattage to achieve it, and how many standard bulbs that translates to.
Proper lighting depends on the room's purpose. Kitchens and offices need bright, even light for tasks (70-80 lumens per square foot), while bedrooms need softer ambient light (30-40 lumens per square foot). Living rooms fall in between at 40-50 lumens per square foot, and bathrooms need good task lighting at 60-70 lumens per square foot.
Modern LED bulbs produce about 80 lumens per watt, making them the most efficient choice. A standard 9-watt LED bulb produces approximately 800 lumens, equivalent to a traditional 60-watt incandescent bulb. The calculator divides your total lumen requirement by 800 to determine how many of these standard bulbs you need.
The annual cost estimate assumes LED bulbs used 5 hours per day at the US average electricity rate of $0.13 per kWh. Layered lighting (combining overhead, task, and accent lights) provides the most versatile and attractive illumination.